Re: Gearbox death throws(Long)

["M Tipton" <miktip@worldnet.att.net>]

    I assume your gearbox is an Audi 5 speed manual?

In my 86 Coupe's gearbox, as with several other Coupe and
4000(80)gearboxes,
(Non Quattro) I've worked on, I have noticed a "trend"
amongst the 5 speed gearboxes!   The differential's right
side outer bearing seems to prematurely wear much earlier
than the other bearings. what this does is allow the
differential the be "out of specifications" and actually
causes it to "bind". Enough to make shifting difficult! 
This is enherent to the design of the gearbox.  

The gearboxes I have repaired have all returned to optimum
shifting
after replacing the right diff bearing and race. Including
my own
162,000 mile gearbox and another 134,000 mile unit.  

I was really suprised upon cracking open a 36,000 mile 86
Coupe GT gearbox
(mainly out of curiosity) and found the right side diff
bearing badly worn!
I aquired the gearbox from a salvage yard, in hopes of
replacing my worn
unit, with the lower mileage one.  Except one weekend I
decided to crack open
my gearbox and see what I could see!  The only thing I
found was the right side
diff bearing badly worn, along with its race and the magnet
in the case cover full of metal particles!  The rest of the
gearbox looked good.  Even the brass syncro's
were good!

I aquired a replacement diff bearing from an Audi dealer,
at $38!  Its was
a "Made in Japan" bearing!  I was suprised Audi was selling
them!

A quick task with a hydraulic press, and the bearing was
installed!
The following day the gearbox was installed, and all the
shifting problems
disappeared !

To ensure this wasnt just a "fluke" I repaired a friends
gearbox in the same manner,
and his shifting problems went away. 

I still have the two bad diff bearings in my tool box!  I
show them off
to people, and most folks are suprised at how bad they're
worn!

It appears the German engineers designed the diff and the
ring and pinion gears 
as a "ruff cut" or "break-in" type of component.  The
36,000 mile gearbox
showed the planetary gears within the diff, could of been
machined to a more 
"smoother" finish.  My 162,000 mile gearbox, has very "worn
smooth" ring and
pinion teeth, as well as planetary gears.  Quite an
astonishing difference between the two! A key to all this
may be the "drive wheel" being right side wheel, and the
right side diff bearing is smaller than the left side
bearing???

In the side case cover(removable side) Audi engineers
installed a large magnet!
At the 9 'o' clock position. On both gearboxes, this magnet
was "full" of metal splinters, and fine shavings! Enough to
fill a tablespoon! 

I have a method of removing the side diff bearing while the
gearbox
is still installed in the car.  However this method
requires the use of a special
puller and backing plate behind the bearing to remove the
bearing.
Instillation is another matter all together!

Although the bearing can be a major cause in shifting
dificulties, you must also
take into consideration the shift linkage!  
                        
                                 M